Making A flow Region is Failing and I Cannot Tell Why

“The flow region could not be created. Please search for potential problems around the following entities”
This is what it says every time I try to create a flow region. I am not sure why this face is directly mirrored across the car and the face on the other side has no issue. It says to do CAD cleanup but I am not sure how I am supposed to clean it up. It does not tell me why the face has faulted so any help would be much appreciated thanks!

Here is the link to my project.

Hello @cyrus_costa , and thanks for posting your question in the Forum!

Your model is quite detailed, and it’s really difficult to determine the cause of the issue when creating the flow region.

When dealing with such external aerodynamics simulations, Hex-Dominant meshing approach could be a good option. This algorithm requires no initial flow region generation, but the mesh is generated based on your inputs in simulation tree. This algorithm will help you to compute fluxes more efficiently, as well as to get a sufficient number of mesh cells to run your simulations.

The following tutorial can be quite helpful in your case: Hex-Dominant Parametric Meshing of Front Wing | SimScale

You could also give it a try with the standard mesher, but the flow region needs to be created first as you’re aware. In this case, using a symmetry flow region actually works. Please just set the Xmin of the external domain to 0, and the flow region should be successful. Apparently the problem is caused from the right side of the vehicle.

I hope this is helpful, and personally I would give the first option a go rather than the standard mesher considering the computational demand.


I am sorry I should have been more specific. It happens when I try and create the external flow region in CAD mode. Not when I try and run the simulation or create the mesh. I cannot even get to the meshing part.

Hello again @cyrus_costa !

Then you could go ahead and use the symmetrical flow region approach, which should work just fine with left side of the vehicle.

Hex-dominant approach was only an alternative suggestion to improve your external aero simulation.